a. Field of Invention
This invention pertains to a filter used for removing particulate matter from a fluid under high pressure, and more particularly to a filter structure having a tubular or cylindrical configuration.
b. Description of the Prior Art
In many industrial processes, a cylindrical filter is required for separating particulate matter from a fluid, said fluid flowing in a radial direction either inwardly or outwardly with respect to a filtering media. Prior art cylindrical filters used for radially outward flow usually included a cylindrical plate formed with a plurality of perforations and a filtering media disposed within the cylinder in the flow path of the fluid. However this type of structure was found to be unsatisfactory for a number of reasons. For example, the perforations had to be spaced sufficiently to insure that the filter structure could withstand the radial forces and consequential hoop stress applied thereto by the high pressure fluid during filtration. However, as a result of this spacing, a large filter was required to be able to handle a given fluid flow. Perforating the plate meant that at least 50% of the plate materials were discarded. Furthermore, at least 50%-60% of the filtering media was blocked. A more open structure could be made only by providing a very thick plate for withstanding the above-mentioned radial forces. Hence the cylindrical filters used in the industry up till now were inefficient and expensive.